Pressurizing arrangement for a compressor



Sept. 9, 1969 R. E. CAWL EY 3,465,949

PRESSURIZING ARRANGEMENT FOR A COMPRESSOR Filed Oct. 23, 1967 INVENIOR. R/CHARD E. CAM/1.5)

United States Patent 01 ice 3,465,949 Patented Sept. 9, 1969 3,465,949 PRESSURIZING ARRANGEMENT FOR A COMPRESSOR Richard E. Cawley, Hurst, Tex., assignor to Lennox Industries Inc.

Filed Oct. 23, 1967, Ser. No. 677,373 Int. Cl. F04b 35/04, 39/06 U.S. Cl. 23058 2 Claims ABSTRACT OF THE DISCLOSURE A refrigerant compressor including a fan for pressurizing the suction gas supplied to the :cylinder means in such compressor. In a refrigerant compressor having an upright crankshaft with an electric motor secured to said drive shaft adjacent the upper end thereof, the fan is secured to the motor so as to pressurize refrigerant gas passing over the motor into the cylinder means to substantially eliminate the adverse effect caused by a suction gas pressure drop as the suction gas passes through the electric motor.

Summary of the invention In the present refrigerant compressor design little cognizance has been taken of suction gas pressure losses occurring in the refrigeration system and in the refrigerant compressor. Before the suction gas enters the cylinders in the compression mechanism for compression by the piston means, movable in such cylinders, suction gas pressure drops are cumulative and adversely affect the B.t.u. per Watt output of the compressor motor. Although various suction gas pressure drops are individually small, they add up and are detrimental to machine operation. Thus, improvement in one or more of the pressure drops will result in improved compressor operation including higher refrigerant capacities.

An object of the present invention is to provide an improved refrigerant compressor having an upright drive shaft with an electric motor secured to the upper end of such drive shaft with a suction gas pressurizing fan connected to the top of the drive shaft for pressurizing suction gas passing over the motor to cool same and at the same time overcoming the pressure drop resulting as such suction gas passes through the compressor motor. Other objects and advantages of the present invention will become more apparent hereinafter.

Brief description of the drawing The attached drawing illustrates a preferred embodiment of my invention in which like numerals refer to like elements, and in which:

FIG. 1 is a side elevational view partly in section and with part broken away of a hermetic refrigerant compressor embodying the present invention;

FIG. 2 is a detail plan View taken generally along the line 2-2 of FIG. 1;

FIG. 3 is a detail cross-sectional view of the pressurizing fan;

FIG. 4 is a cross-sectional view of a semi-hermetic refrigerant compressor embodying suction gas pressurizing means; and

FIG. 5 is a detail view of the fan construction shown in FIG. 4 taken generally along line 5-5.

Description of presently preferred embodiments Referring to FIG. 1, there is illustrated a compressor embodying the present invention. The compressor 10 comprises a hermetic outer housing including an upper shell 12 and a lower shell 13 integrally joined to one another in gas-tight relationship, as for example, by Welding. To the bottom of the exterior surface of the lower shell 13 are secured a plurality of legs 14. The legs 14 support the compressor in an upright position within a condensing unit or air conditioning unit.

Resiliently supported in the housing by means of conventional spring means 15 is a compression mechanism 16 which includes a compressor block 18 having a plurality of cylinder means 20 defined therein. Within the radially-oriented cylinders 20 are annular cylinder sleeves or liners and slidably guided in each of the cylinder liners 20 is a piston 22. Each piston 22 has mounted therein a Wrist pin 24 upon which is journaled one end of a connecting rod 26. The other end of each connecting rod 26 is connected to the drive shaft or crank shaft 28.

Provided at the outer end of each of the cylinders 20 in the compressor block 18 are discharge and suction valve assemblies 30 for controlling the flow of refrigerant gas. Such valve assemblies 30 may comprise a discharge valve unit 32, a suction valve plate 34 and a suction valve or reed member 36. The valve assemblies are operative in a known manner. Each valve assembly 30 is held in place in the end of an associated cylinder by a cylinder head or cape 38. A Belleville spring 39 and a retaining ring 40 cooperate with the head 38 to maintain the head 38 in position closing the end of the cylinder. O-ring 41 is provided to seal the head 38 with respect to the Wall defining the cylinder 20.

As shown, an annular sleeve 42 is disposed about the compressor block 18 and cooperates with the exterior of the compressor block 18 to define a discharge gas manifold cavity within the compression mechanism 16. A heat shield 44 is disposed concentrically about the annular sleeve 42 for minimizing heat transfer between the relatively hot discharge gas in the discharge gas muflling cavity within the compression mechanism and the relatively cold suction gas disposed in the annular space between the compression mechanism 16 and the outer housing.

The upright crankshaft or drive shaft 28 is suitably journaled within the compressor block by means including upper bearings 46 and 47 and lower bearings (not shown). Provided in the crankshaft are lubricating means for lubricating the crankshaft bearing surfaces and the connecting rod bearing surfaces. To the upper end of the drive shaft 28 there is connected the rotor of an electric drive motor 48. The motor 48 comprises a stator 49 which is supported Within the upper portion of the compressor block 18 defined in part by an upwardly extending annular ring-like portion 18a. The stator 49 is inductively connected to a rotor 50 which is operatively afiixed to the upper portion of the crankshaft 28 by suitable means, as for example, a key or by shrinking the rotor onto the drive shaft or crankshaft 28.

Suction gas enters the compressor 10 through a suction gas fitting 59 which is adapted to be connected to the suction line in a refrigeration system. The suction gas flows into the annular space between the compression mechanism 16 and the outer housing or casing of the compressor 10. The gas then passes through the suction gas pressurizing means indicated generally at 62, over the compressor motor 48 for cooling same, and through openings 21 in the compressor block into the cylinders 20 within the compressor block 18. The refrigerant gas is compressed by the pistons 22 and discharged through the discharge and suction gas valves 30 into the discharge gas mufiiing chamber within the compressor block 18. A discharge line 68 is connected at one end to the discharge gas mufiling chamber. At the other end the discharge line is provided with a discharge fitting 69 which connects to the conduit communicating the discharge line 68 with a heat exchanger in a refrigeration system.

Considering now in more detail the suction gas pressurizing means 62, it is noted that there are suction gas pressure losses occurring in the refrigeration system and in the refrigerant compressor prior to the suction gas entering the cylinders for compression. For example, there is a pressure drop as the suction 'gas passes over the compressor motor 48. The suction gas pressurizing means 62 functions to increase the pressure of the suction gas and thereby overcome some of the pressure losses with the result that the suction gas pressure drops that adversely affect the refrigerant capacity of the compressor are minimized. As shown in FIGS. 1-3, the suction gas pressurizing means 62 comprises a fan member 64 cooperating with an annular shroud or cage 65 defining chambers 66 therein which communicate with the fan 64 and which has openings 67 defined in the bottom thereof. The fan 64 comprises a base portion 64a and a top plate 64b spaced apart by blades 640. The blades 640 are provided with offset or angled flanges at each end for connection to the top and bottom members, as for example, by welding to form the fan. The inner end of each blade is secured to hub 61 carried on shaft 28. Suction gas enters the pressurizing means 62 through an opening 60 defined in the top 64]) thereof in alignment with the crankshaft. The suction gas passes into the shroud 65, which includes top and bottom members 65a and 65b secured in spaced relationship by blades or guide vanes 65c and defining chambers 66 therebetween. The suction gas pressurizing means functions to increase the pressure of the suction gas to compensate for pressure drops occurring as the suction gas passes over the motor 48 to cool same, as Well as to overcome other pressure drops in the refrigerant system. The result is an increase in compressor capacity and a cooler motor due to the increased flow rate of suction gas over the motor and the guided flow distribution over the motor through the plurality of equally-spaced openings 67 in the shroud 65 or fan cage. Preferably, there is an opening 67 associated with each of the plurality of chambers 66 defined by the blades 650 within the shroud 65 and the number of blades in the shroud is equal to the number of blades in the fan 64.

Tests were conducted upon a refrigerant compressor having the suction gas pressurizing means of the present invention and comparable tests were made on the same compressor wherein the suction gas pressurizing means were omitted. The results of the tests are tabulated below:

Conditions: 125: F. condensing temp, F. evaporating temp., F. return gas, and zero subcooling compartment, inches oil 1 Pressure increase in motor compartment over suction gas as it enters the compressor.

In the present design, the suction gas pressurizing means functions to give a higher capacity for a given reciprocating design inasmuch as there is in effect a booster provided in the suction gas stream before the suction gas enters the cylinders 20. Because of the pressurized flow of suction gas, the motor operates in a cooler manner. In addition, there is less oil carryover resulting from the pressurized motor compartment which contains the hearing housing.

Referring to FIG. 2, there is illustrated the construction of the fan 62 and the location of the openings 67 within the housing portion are also shown. It will be noted that the openings 67 are spaced about the axis of the crankshaft to provide for a uniform distribution of suction gas over the motor 48, with an opening 67 providing an exit from each space 66 defined in the shroud 65.

Referring to FIGS. 4 and 5, there is illustrated a modification of the present invention wherein pressurizing means 162 are provided for pressurizing suction gas entering the cylinders in compressor 100. The essential difference between the two compressor constructions is that in the design of FIG. 1, the electric motor 48 is incorporated within the hermetic outer housing of the compressor 10 whereas in the design of FIG. 3 the electric motor is adapted to be disposed outside of the housing of the compressor 10 and connected to the drive shaft in a suitable known manner. It will be understood that a piston 122 is adapted to reciprocate within each cylinder liner 123 for compressing suction gas entering the compressor through a suitable suction gas inlet 159. The suction gas passes through opening into the pressurizing means 162 and from the pressurizing means 162 into the passage 170 and into the chamber defined above the piston 122. The gas is compressed within the chamber and passes through the discharge and suction valve assembly 130 into the discharge gas cavity 172 from which it is discharged through the discharge opening 168 into the discharge line which communicates the compressor with the condenser in a refrigeration system.

As shown in the drawing (FIGS. 4 and 5), the pressurizing means 162 includes a fan 164 constructed in a manner similar to fan 64. Fan 164 includes spaced generally parallel members 164a and 16% and radially disposed blades 164c. Disposed about the fan 164 is a shroud or cover 165 which is retained in place on the compressor block 118 by a retaining ring 180.

The pressurizing means 162 is used to supercharge or increase the suction gas pressure prior to entry of the suction gas into the cylinders of the compressor for compression. Suction gas losses in the refrigeration system are minimized, and refrigeration capacity of the compressor is increased.

There has been provided by the present invention a refrigerant compressor of improved design having within the refrigerant compressor suction gas pressurizing means for pressurizing the suction gas supplied to the cylinders for compression. In a preferred embodiment of the present invention, the suction gas pressurizing means is disposed adjacent to the compressor motor in a hermetically closed refrigerant compressor for pressurizing suction gas passing over the motor to increase the flow rate over the motor to enhance the cooling of same and so as to pressurize the suction 'gas supplied to the cylinders. The result of suction gas pressure increase is to increase the capacity of the refrigerant compressor.

While I have shown presently preferred embodiments of my invention, it will be understood that my invention is not limited thereto, since it may be otherwise embodied Within the scope of the following claims.

What is claimed is:

1. In a refrigerant compressor, a closed housing, compression mechanism within said housing including cylinder means and piston means operatively connected to an upright drive shaft and movable within said cylinder means, an electric drive motor in said housing for rotating said drive shaft to actuate the piston means, discharge and suction valve means associated with said cylinder means for controlling the flow of refrigerant gas, means communicating suction gas to said housing, said suction gas being passed over said electric drive motor to cool same prior to passage into said cylinder means, means communicating discharge gas from said housing and pressurizing means within said housing for pressurizing all of the suction gas passing over the electric drive motor and supplied to the cylinder means for compression by the piston means to overcome suction gas pressure losses including the pressure drop resulting as the suction gas passes over the electric drive motor, said pressurizing means comprising a shrouded fan on the drive shaft and disposed between the suction gas communicating means and the cylinder means.

2. A refrigerant compressor as in claim 1 wherein the compression mechanism is spaced from said housing to define a suction gas chamber between the compression mechanism and the housing, the suction gas from said suction gas communicating means passing into said suction gas chamber, then over said electric drive motor into said cylinder means, said fan being secured to said drive shaft above the electric drive motor.

References Cited UNITED STATES PATENTS 2,509,377 5/1950 Trask 23045 2,963,218 12/1960 Tower 23058 XR 3,075,106 1/ 1963 Chi.

3,145,914 8/1964 Nicholas 23058 XR ROBERT M. WALKER, Primary Examiner US. Cl. X.R. 230208 

